JL Audio HD900/5 Review

After growing tired of dedicating 12.5” x 40” to three amplifiers over my rear axle hump, I decided that it was time to purchase a JL Audio HD900/5 and see if it would meet or exceed my expectations. I finally have the amplifier installed, and I must say that I was a little leery about giving up a little power here and there to run the 900/5. Well, now that it is in there, and tuned the way I liked it, I must say that my power deficit concerns were irrevelant. Just in case anyone wants to know, here are my system specifications: Alpine CDA-9887 source; Tang Band W4-1757SB (500 Hz on up); Mach5 Audio MLI-65 (80 to 500 Hz); Subwoofer – 13w6v2 Mustang Stealthbox (80 Hz on down).

Thus far, I have limited listening with the amplifier, but Pink Floyd - Dark Side of the Moon sounds GREAT. I also listened to a few tracks from Nine Inch Nails - The Fragile, and I was impressed. The imaging in Somewhat Damaged is spot on and the midbass in We’re In This Together is most certainly there. I also cranked up the volume on Killasound by Freestylers vs Wizard just to see if I would notice the 350 watt power deficit on my subwoofer. I must say, the theoretical 2.55 decibel loss in subwoofer output by going from 850 watts to 500 isn’t as noticeable as I thought it would be. If anything, the subwoofer appears to blend better at all volume levels versus being overpowering at times.

Any concerns I once had about full range class D are now moot. Granted, it was hard to get past the stigma of the Alpine PDX-5 that I tried in 2008, but this amplifier literally smokes it. My complaints about the Alpine were lack of midbass, lack of subwoofer output, and noise. I am happy to report that the JL Audio HD900/5 has NONE of these issues! If you are tired of dedicating a whole bunch of real estate to multiple amplifiers and are on the fence about purchasing a 900/5, my advice is to purchase it!

Lastly, other options I considered were the Kenwood XR4s with a XR1; Alpine PDX F4 with a PDX M6; and the JL Audio 600/4 with a HD750/1. The reason the HD900/5 won out was due to the fact that I get everything in one amplifier!

I keep saying that I'd use two of these in a 3-way system and be done. I've almost ditched my 2 HD600/4s + 750/1 to go with this option but loathe the idea of dealing with power wires again.

The thing I really like about the HD amps (and other mfg's do this now) is they have ALL their connections in a plug interface. So, you can wire up the amp rack or system, drop the amps in, plug the plugs in and you're done. No hunching over the car to tighten down wires, etc. Very convenient.

I have been listening to all kinds of familiar source material just trying to find a note that the full range class d amplifier will produce differently than what I remembered. I must admit that I can not do it, no matter what I listen to or how hard I try. In fact, this is the first time since re-entering car audio as a hobby in 2007 that I have spent this much time performing critical listening with the car just sitting under the carport. As an aside, I must admit that having an IOTA DLS-55 with the built-in IQ4 function makes those long listening sessions so much easier than idling the car the whole time.